C=15+3. Combine like terms. C=18.
Answer:

Step-by-step explanation:
From the figure attached,
ΔABC is an equilateral triangle.
Therefore, by the property of the equilateral triangle,
Measure of each angle = 60°
By applying tangent rule in the right triangle ADC,





Step-by-step explanation:
Permutation
:The number of ways to choose a sample of r elements from a set of n distinct objects where order does matter and replacements are not allowed.

Factorial
: There are n! ways of arranging n distinct objects into an ordered sequence.
Considering a situation when n = r in a permutation, nPr reduces to n!, a simple factorial of n.
Proof: 3P3 = 3!
n = 3 and r = 3

But 0! = 1
3P3 = 3!
Answer:
A.The data should be treated as paired samples. Each pair consists of an hour in which the productivity of the two workers is compared.
Explanation:
If the mean productivity of two workers is the same.
For a random selection of 30 hours in the past month, the manager compares the number of items produced by each worker in that hour.
There are two samples and the productivity of the two men is paired for each hour.